5 Things Architects Need to Know About Envelopes with Metal Wall Panels and Continuous Insulation

by Christopher Brinckerhoff | June 1, 2021 12:00 am

1. Assess Material Availability

One thing architects can do early on in the design process to improve coordination with fabricators is assess material lead times and availability. Checking with fabricators and manufacturers, architects can find out what materials are readily available and how long they may take to reach the job site. There are other implications, as well. For example, in terms of the metal panels, different types come in different sizes, which affects a design, and different metal panel types work in envelopes differently too.

Jeff Briant, preconstruction manager at Decatur, Ga.-based Henry Inc., says, “The biggest thing for architects is just the material availability with the panel type that they are wanting on a project, and that’s because there are limitations. If it’s an aluminum panel, it may only be 4-foot by 8-foot. If it is an aluminum composite panel system, they manufacture those sheets 62 inches by 196 inches, so you can have a larger panel with the composites than you can with single-skin aluminum plate.”

2. Tested Assemblies Versus New Assemblies

James Hatch, vice president of preconstruction at Chandler, Ariz.-based Kovach Enclosure Systems LLC, says architects are often interested in discussing ensuring their wall assemblies meet National Fire Protection Association’s (NFPA) 285 fire test method requirements.

“When I think about conversations with architects, that comes up a lot. NFPA 285 is really a combination of products and a lot of times it requires you to test the assemblies. Whereas you might just have one product that passes, but you have to get the whole assembly to pass. We spend a lot of time taking our designed walls through labs to make sure that they would pass.”

One thing architects should be aware of is if they intend to use a wall assembly that hasn’t been tested and used before, it will add time to the design process, Hatch says.

“[Testing an assembly with NFPA 285 is] ultimately what the designer, the consultant and the owner will accept. A lot of times an engineering judgement doesn’t suffice. They’ll say we want to see that this assembly has been tested and proven; so that’s what we do. And at times, it adds time to a project. And architects need to be aware that if they are doing something that is newer and is an assembly that hasn’t gone through those testing requirements, it’s going to add a few months to their job. So NFPA 285 does play into exterior continuous insulation.”

3. Anticipate Thickness

Insulation thickness is often a topic of conversation related to envelopes with continuous insulation because it can be surprising how thick it needs to be, Briant says.

“The thickness of the insulation—and that would encompass Z-girts—all of that starts with what R-value you are trying to achieve on the exterior of the building. That’s going to determine the thickness of the rigid insulation. From that point, when directing architects, it’s taking into account the thickness of the insulation, then the panel system. We want to show them how far away the panel is from the substrate of the building. For example, at an opening, they may not expect that the depth of the panel return to be a system thickness of 2 inches plus rigid insulation of 2 inches. So, they may not expect that their window could look 4 inches recessed if you’re viewing in elevation.”

4. Z-girts: Metal versus Fiberglass

One detail in envelopes with continuous insulation designers and contractors should watch for is the type of Z-girts that attach panels to building substrates, Hatch says. To avoid thermal breaks, fiberglass Zs are used instead of galvanized steel Zs.

“A lot of times there’s misunderstanding between the architect and the contractor, that they might list this is a continuous insulation project, we want a Rockwool product, but they’ll neglect to specify the need for a fiberglass Z in lieu of a galvanized Z, and that’s a gray area that there’s a pretty substantial cost difference between those two. Most subs would say I want to be competitive, here’s your exterior air insulation quote, but we did not include the fiberglass Z, which is usually important in a lot of these applications.”

5. Determine Panel Layout

Architects can improve communication with fabricators and, potentially, reduce material waste and cost in projects with metal panels and continuous insulation by including panel placement in drawings, Briant says.

“On the types of projects we go after, there are reveals. [The reveals are] never placed on drawings by architects, which may be one of the helpful things to do. In our drawing process we insert what we think the architects may want, and it may go back and forth with revisions until the architect [says,] ‘I want this; no, I want that. I want this line here, not there.’ If they predetermine the layout that they’re requesting, that’s always helpful.”

Designing the panels with the raw material size and panel placements in mind, the raw material can be maximized to reduce waste and cost, Briant says.

“When understanding the different sizes of materials, and predetermining panel sizes, architects can find out if they are utilizing the material to its best yield, meaning not having a lot of waste. A lot of times what drives costs up is wasteful material, and you can reduce waste and cost to the owner of the building.”

Source URL: https://www.metalarchitecture.com/articles/5-things-architects-need-to-know-about-envelopes-with-metal-wall-panels-and-continuous-insulation/

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